This invention relates to a method of preparing aluminum so as to resist pitting. Generally, aluminum is protected by an oxide film that forms on its surface and restricts the access of the environment to the metal. The thickness of the oxide can be varied by anodizing the material, which involves polarizing the metal electro-positively in an electrolyte. Pitting is a localized corrosion process on aluminum that can occur in chloride-containing environments. There is no effective way of improving the resistance of aluminum to pitting without adding inhibitors to the solution to which the metal is exposed. Although anodizing does result in increasing the time required to initiate a pit, the thermodynamic propensity of a pit to form does not change.